Gripper devices

Abstract

Systems are provided for gripping or otherwise manipulating lettuce, sliced foodstuffs (e.g., sliced cheese, sliced tomato or other sliced vegetables), or other foodstuffs or other irregular objects or substances. These systems can facilitate the manipulation of groups of irregular objects, including distributing small amounts (e.g., individual instances) of such groups of objects. These systems operate to manipulate such objects by extending and retracting rods, wires, or otherwise-configured pins to contact and/or penetrate the object(s) to be manipulated. In some examples, the pins are retracted to individually dispense objects (e.g., slices of cheese) from a stack of objects. In some examples, the separation and angle of the pins can be controlled to, e.g., grip one or more irregular objects and subsequently to dispense some or all of the gripped object(s).

What is claimed is: 
     
       1. A gripper apparatus comprising:
 a first iris, wherein the first iris comprises: (i) a first static plate having a first plurality of openings therein, and (ii) a first rotatable plate having a second plurality of openings therein, wherein the first rotatable plate has a first axis of rotation, and wherein the first rotatable plate is rotatable, relative to the first static plate, about the first axis of rotation; 
 a second static plate having a third plurality of openings therein; 
 a push plate that is slidably movable relative to first iris and the second static plate, wherein the first static plate and the first rotatable plate are disposed between the push plate and the second static plate; and 
 a plurality of flexible wires, wherein each respective wire of the plurality of flexible wires is disposed within a respective opening of the first plurality of openings, a respective opening of the second plurality of openings, and a respective opening of the third plurality of openings such that rotation of the first rotatable plate relative to the first static plate results in a change in a distance between the respective wire and the first axis of rotation of the first rotatable plate, and wherein each wire of the plurality of flexible wires is mechanically coupled to the push plate such that motion of the push plate, relative to the first iris and the second static plate, results in longitudinal motion of the plurality of wires through the first, second, and third pluralities of openings. 
 
     
     
       2. The apparatus of  claim 1 , wherein the first plurality of openings comprises a plurality of linear slots, and wherein the second plurality of openings comprises a plurality of spiral slots. 
     
     
       3. The apparatus of  claim 1 , further comprising:
 a second iris, wherein the second iris comprises: (i) the second static plate, and (ii) a second rotatable plate having a fourth plurality of openings therein, wherein the second rotatable plate has a second axis of rotation, wherein the second rotatable plate is rotatable, relative to the second static plate, about the second axis of rotation, and wherein each respective wire of the plurality of flexible wires is disposed within a respective opening of the fourth plurality of openings such that rotation of the second rotatable plate relative to the second static plate results in a change in a distance between the respective wire and the second axis of rotation of the second rotatable plate. 
 
     
     
       4. The apparatus of  claim 3 , further comprising:
 a tube, wherein the tube is coupled to the first rotatable plate, and wherein the tube has a channel along a rotational axis of the tube; and 
 a rod, wherein the rod is coupled to the second rotatable plate, and wherein the rod is disposed within the channel of the tube. 
 
     
     
       5. The apparatus of  claim 1 , further comprising a plurality of pointed tips,
 wherein each respective wire of the plurality of flexible wires is coupled to a respective pointed tip of the plurality of pointed tips. 
 
     
     
       6. The apparatus of  claim 1 , further comprising:
 at least one sensor mechanically coupled to at least one wire of the plurality of flexible wires, wherein the at least one sensor is operable to detect at least one of whether at least one wire is penetrating an object or a force applied along a longitudinal direction of the at least one wire. 
 
     
     
       7. The apparatus of  claim 6 , wherein the at least one sensor comprises a plurality of piezoelectric actuators coupled to the at least one wire, wherein each piezoelectric actuator is operable to generate at least one of an axial vibration in the at least one wire or a transverse vibration in the at least one wire. 
     
     
       8. The apparatus of  claim 1 , wherein at least one wire of the plurality of wires has a channel formed therein. 
     
     
       9. A method for gripping individual items in a stack of items, the method comprising:
 positioning a gripper apparatus proximate to a stack comprising a plurality of items in a stacked arrangement, and wherein the gripper apparatus comprises: 
 a first push plate, wherein a first plurality of pins are coupled to the first push plate, and wherein the pins of the plurality of first pins are substantially parallel to each other; 
 a second push plate, wherein a second plurality of pins are coupled to the second push plate, wherein the pins of the plurality of second pins are substantially parallel to each other, and wherein pins of the first plurality of pins are substantially non-parallel to pins of the second plurality of pins; and 
 a guide plate having a contact surface, wherein the guide plate has formed therein a first plurality of channels extending from the contact surface and a second plurality of channels extending from the contact surface, wherein the first push plate is disposed relative to the guide plate such that the pins of the first plurality of pins are disposed within respective channels of the first plurality of channels, wherein the second push plate is disposed relative to the guide plate such that the pins of the second plurality of pins are disposed within respective channels of the second plurality of channels, and wherein the first push plate and the second push plate are slidably movable relative to the guide plate such that the first push plate and the second push plate can be moved relative to the guide plate to result in the first plurality of pins and second plurality of pins, respectively, protruding from the contact surface; 
 actuating the first push plate and the second push plate of the gripper apparatus such that the first plurality of pins and the second plurality of pins protrude from the contact surface and penetrate at least a portion of the stack; 
 moving the gripper apparatus to a first location; 
 actuating the first push plate and the second push plate of the gripper apparatus to partially retract the first plurality of pins and the second plurality of pins into the guide plate such that a first item in the stack is dispensed at the first location; 
 moving the gripper apparatus to a second location; and 
 actuating the first push plate and the second push plate of the gripper apparatus to further retract the first plurality of pins and the second plurality of pins into the guide plate such that a second item in the stack is dispensed at the second location. 
 
     
     
       10. The method of  claim 9 , wherein the gripper apparatus further comprises a sensor that is coupled to at least one pin of the first plurality of pins, and wherein the method further comprises:
 while actuating the first plate and the second plate of the gripper apparatus such that the first plurality of pins and the second plurality of pins protrude from the contact surface and penetrate at least a portion of the stack, operating the sensor to detect how many items are present in the stack. 
 
     
     
       11. The method of  claim 9 , wherein the gripper apparatus further comprises a sensor that is coupled to at least one pin of the first plurality of pins, and wherein the method further comprises:
 while actuating the first push plate and the second push plate of the gripper apparatus to partially retract the first plurality of pins and the second plurality of pins into the guide plate such that a first item in the stack is dispensed at the first location, operating the sensor to detect whether the first item has been dispensed, wherein actuating the first push plate and the second push plate of the gripper apparatus to partially retract the first plurality of pins and the second plurality of pins into the guide plate such that an item is dispensed at the first location comprises actuating the first push plate and the second push plate to partially retract the first plurality of pins and the second plurality of pins into the guide plate until the sensor detects that the first item has been dispensed. 
 
     
     
       12. The method of  claim 9 , wherein at least one pin of the first plurality of pins has formed therein a channel that terminates in at least one aperture formed proximate an end of the at least one pin, and wherein the method further comprises:
 applying a gas or liquid, via the channel of the at least one pin, to separate the first item from the second item. 
 
     
     
       13. The method of  claim 12 , wherein the gas or liquid is applied while actuating the first push plate and the second push plate of the gripper apparatus to partially retract the first plurality of pins and the second plurality of pins into the guide plate such that the first item in the stack is dispensed at the first location. 
     
     
       14. The method of  claim 12 , further comprising:
 cleaning the gripper apparatus, wherein cleaning the gripper apparatus comprises applying a cleaning fluid via the channel of the at least one pin. 
 
     
     
       15. A gripper apparatus comprising:
 a first push plate, wherein a first plurality of pins are coupled to the first push plate, and wherein the pins of the plurality of first pins are substantially parallel to each other; 
 a second push plate, wherein a second plurality of pins are coupled to the second push plate, wherein the pins of the plurality of second pins are substantially parallel to each other, and wherein pins of the first plurality of pins are substantially non-parallel to pins of the second plurality of pins; and 
 a guide plate having a contact surface, wherein the guide plate has formed therein a first plurality of channels extending from the contact surface and a second plurality of channels extending from the contact surface, wherein the first push plate is disposed relative to the guide plate such that the pins of the first plurality of pins are disposed within respective channels of the first plurality of channels, wherein the second push plate is disposed relative to the guide plate such that the pins of the second plurality of pins are disposed within respective channels of the second plurality of channels, and wherein the first push plate and the second push plate are slidably movable relative to the guide plate such that the first push plate and the second push plate can be moved relative to the guide plate to result in the first plurality of pins and second plurality of pins, respectively, protruding from the contact surface. 
 
     
     
       16. The apparatus of  claim 15 , further comprising:
 a housing, wherein the guide plate is removably mounted to the housing such that the guide plate can be removed from the housing when the first plurality of pins and the second plurality of pins are fully retracted from the guide plate. 
 
     
     
       17. The apparatus of  claim 15 , further comprising at least one sensor that is coupled to at least one pin of the first plurality of pins, wherein the at least one sensor is operable to detect a force applied along a longitudinal direction of the at least one pin. 
     
     
       18. The apparatus of  claim 15 , wherein at least one pin of the first plurality of pins has formed therein a channel that terminates in an aperture formed at the end of the first pin. 
     
     
       19. The apparatus of  claim 15 , wherein at least one pin of the first plurality of pins has formed therein a channel that terminates in an aperture formed through a lateral surface of the first pin. 
     
     
       20. The apparatus of  claim 15 , further comprising an actuator, wherein the actuator is operable to slidably move the first push plate and the second push plate relative to the guide plate to result in the first plurality of pins and second plurality of pins, respectively, moving within respective sets of channels within the guide plate. 
     
     
       21. The apparatus of  claim 20 , further comprising:
 a first linking rod, wherein the first linking rod is mechanically coupled to the actuator via a first pin, and wherein the first linking rod is mechanically coupled to the first push plate via a second pin; and 
 a second linking rod, wherein the second first linking rod is mechanically coupled to the actuator via a third pin, and wherein the second linking rod is mechanically coupled to the second push plate via a fourth pin.